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Guam • Live Time Zone Guide

Guam Time Zone

Guam uses Chamorro Standard Time (ChST), UTC+10:00, all year. Guam does not currently observe daylight saving time, so Hagåtña, Dededo, Tamuning, Yigo, Mangilao, Barrigada and every other community on the island keep the same UTC+10:00 civil clock in every season.

Guam time zone = ChST = UTC+10:00 year-round. For software, calendars and historical timestamps, use the IANA identifier Pacific/Guam. Guam's clock itself does not move seasonally; changing differences with Los Angeles, New York or Sydney happen because those locations may change their clocks.
Time zones1 islandwideChamorro Standard Time
UTC offsetUTC+10:00Fixed all year
IANA zonePacific/GuamNo current DST
See Guam's Time Zone Time Zone Converter Guam on the Oceania Time Zone Map
Search a Guam location, ChST, UTC+10, IANA zone, DST question or related Oceania time-zone reference.
Popular: Time in Guam Japan Time Zone Australia Time Zone UTC Offsets Time Zone Converter Oceania Time Zone Map

Guam Time Zone at a Glance

Modern Guam has one simple civil clock, but its relationship to the mainland United States is unusual enough that the date can differ as well as the hour.

ChST

Chamorro Standard Time

See Guam's nationwide UTC+10:00 rule and the official U.S. time-zone designation.

See ChST details → IANA

Pacific/Guam

Learn why this location-based identifier is the right choice for modern and historical Guam timestamps.

See the IANA zone → DST

No Current Daylight Saving Time

Guam does not change clocks today, although the island did observe DST irregularly in the twentieth century.

See DST history → USA

Guam vs U.S. Mainland

See why Guam can be 14–18 hours ahead of mainland U.S. cities and often on the next calendar day.

Compare U.S. zones → ⇄

Guam vs Asia-Pacific

Compare Guam with Japan, Brisbane, Sydney, Honolulu and other high-signal reference locations.

Compare live times → ↔

Guam Time Converter

Convert Guam time for any date and automatically account for DST at the other location.

Open converter →

Guam's One Islandwide Time Zone

Guam is a U.S. territory, but it does not use any mainland U.S. time zone. The island has its own U.S. standard-zone designation: Chamorro Standard Time.

Open Guam's live clock →
Time ZoneAbbreviationUTC OffsetIANA ZoneDaylight Saving
Chamorro Standard TimeChSTUTC+10:00Pacific/GuamNot observed
See Guam Communities Explore UTC+10:00 Convert Guam Time

Guam Time Zone Locations

Guam's capital, largest villages, resort districts and military-adjacent communities all use the same Pacific/Guam clock.

CapitalHagåtñaPacific/Guam · ChST · UTC+10:00→ Northern GuamDededoSame ChST clock as Hagåtña.→ Tourism & BusinessTamuningUTC+10:00 year-round.→ Northern GuamYigoSame Pacific/Guam civil time.→ Central GuamMangilaoChST · UTC+10:00 year-round.→ Central GuamBarrigadaSame islandwide time zone.→ Territory ClockCurrent Time in GuamLive Guam current-time reference.→ Visual GeographyOceania Time Zone MapSee Guam in the western Pacific time-zone system.→

Major Guam Communities — Same Time Zone

These live rows demonstrate the islandwide rule: every listed community resolves to the same ChST / UTC+10:00 civil time.

See current time in Guam →
LocationAreaIANA ZoneCurrent TimeAbbreviationUTC Offset
HagåtñaCapitalPacific/GuamLive——
DededoNorthern GuamPacific/GuamLive——
TamuningCentral / West CoastPacific/GuamLive——
YigoNorthern GuamPacific/GuamLive——
MangilaoCentral GuamPacific/GuamLive——
BarrigadaCentral GuamPacific/GuamLive——
YonaEastern GuamPacific/GuamLive——
Santa Rita-SumaiSouthern GuamPacific/GuamLive——

Practical rule: if it is 9:00 AM in Hagåtña, it is also 9:00 AM in Dededo, Tamuning, Yigo, Mangilao and every other community on Guam.

U.S. Territory · Western Pacific Clock

Guam Is UTC+10:00 All Year

NIST lists Chamorro Time as a U.S. time zone with ChST at UTC+10 and no daylight-time counterpart. The National Weather Service in Guam likewise places Guam and the Northern Mariana Islands at UTC+10. That fixed offset makes Guam one of the earliest U.S. jurisdictions to enter each new calendar day.

Guam vs U.S. Mainland UTC Offsets Japan Time Zone Australia Time Zone
HagåtñaLive timeLoading UTC offset
DededoLive timeLoading UTC offset
TamuningLive timeLoading UTC offset
YigoLive timeLoading UTC offset

Guam Time Difference from the U.S., Japan & Australia

Guam is a U.S. territory but sits far west of the mainland in the Pacific. The clock difference is large enough that the calendar date often changes too.

Convert a specific date and time →
LocationIts Rule FamilyDifference from GuamWhat Changes
New YorkEST ↔ EDTGuam +15h on EST; +14h on EDTNew York changes clocks; Guam does not.
Los AngelesPST ↔ PDTGuam +18h on PST; +17h on PDTLos Angeles observes U.S. DST.
HonoluluHST · UTC−10:00 fixedGuam +20hBoth Guam and Hawaii avoid DST, so the clock gap stays fixed.
JapanJST · UTC+09:00 fixedGuam +1hBoth use fixed current offsets year-round.
BrisbaneAEST · UTC+10:00 fixedSame timeQueensland does not observe DST, matching Guam's UTC+10 clock.
SydneyAEST ↔ AEDTSame on AEST; Sydney +1h on AEDTNew South Wales observes DST; Guam does not.
Northern Mariana IslandsChST · UTC+10:00 fixedSame timeGuam and the Northern Mariana Islands share Chamorro Standard Time.

Date-line effect: “20 hours ahead of Hawaii” does not mean the two places are almost a full day apart in elapsed time for every practical comparison—the date label also matters. A Guam time can fall on the next calendar day relative to Hawaii or the continental United States.

Japan Time Zone Australia Time Zone Open Full Converter

Does Guam Observe Daylight Saving Time?

No. Guam does not observe daylight saving time in 2026. NIST explicitly lists Guam among the U.S. regions that do not use DST, and Guam has no current spring-forward or fall-back transition.

2026No DST start date and no DST end date. Guam remains ChST / UTC+10:00 all year.
U.S. mainland comparisonMost mainland U.S. locations change clocks, so their difference from Guam shifts by one hour even though Guam stays fixed.
Northern Mariana IslandsThe neighboring U.S. commonwealth also uses ChST at UTC+10 without current DST.

Guam's Historical DST & the 2000 ChST Name

Modern Guam is fixed at UTC+10, but historical timestamps require more care. IANA records irregular Guam daylight-saving rules in the twentieth century.

1959–1977IANA release notes describe Guam as observing DST irregularly during this period.
1977 final DST seasonThe tzdb records a spring advance on April 24 and a return to standard time on August 28, 1977.
December 23, 2000The tzdb changes the displayed standard-time label from GST to ChST while keeping the UTC+10:00 offset. This is an abbreviation change, not a one-hour clock change.

ChST vs UTC+10 vs Pacific/Guam

These labels describe different layers of the same modern Guam time system.

ChST

Chamorro Standard Time

The U.S. standard-time name used for Guam and the Northern Mariana Islands. In Guam, ChST is UTC+10:00 year-round.

UTC+10:00

The Current Offset

Guam is ten hours ahead of Coordinated Universal Time. The modern offset does not change with the seasons.

IANA

Pacific/Guam

The preferred location-based identifier for Guam because it preserves historical transitions as well as today's fixed rule.

U.S. Time Zone

Not Pacific Time

Guam is a U.S. territory, but it is not in U.S. Pacific Time. ChST is far ahead of PST/PDT and has different daylight-saving rules.

Regional Match

Same Clock as the Northern Marianas

Saipan, Tinian and Rota in the Northern Mariana Islands also use ChST at UTC+10:00 under current rules.

Historical Dates

Do Not Hardcode UTC+10 Forever

UTC+10 is correct for modern Guam, but historical records include earlier local offsets, wartime changes and irregular DST. Use Pacific/Guam for past dates.

Quick Guam Time Zone Compare

Compare Guam with high-signal U.S. and Asia-Pacific locations. Guam stays fixed at UTC+10:00; seasonal rules elsewhere are applied automatically.

Live time
Current abbreviation and UTC offset
⇄
Live time
Current abbreviation and UTC offset
Open Full Converter

How Guam's Time Zone Works

Six rules explain nearly every modern Guam time-zone question.

01 · One Zone

Guam Has One Current Civil Time Zone

There are no village-level or regional time-zone differences anywhere on the island.

02 · Offset

Guam Is UTC+10:00

Ten hours are added to UTC. This modern relationship remains fixed throughout the year.

03 · ChST

Chamorro Standard Time Is the U.S. Zone Name

NIST lists ChST as the standard-time abbreviation for the Chamorro time zone at UTC+10.

04 · IANA

Use Pacific/Guam

This identifier handles Guam's current rule and its more complicated historical timeline.

05 · No DST

Guam Does Not Change Clocks Today

There is no current spring-forward or fall-back. Differences move only when the comparison location changes.

06 · Date

The Calendar Day Often Differs from the U.S.

Because Guam is far ahead of mainland U.S. zones, a call can cross midnight and land on a different local date.

IANA Time Zone vs Guam ChST

ChST is the readable zone name used for Guam's current standard time. Pacific/Guam is the IANA identifier to store when software must interpret actual dates. A plain UTC+10:00 offset is enough for a modern instant, but it cannot represent Guam's historical DST, wartime changes or older local mean time.

Pacific/Guam · Guam current time UTC+10:00 · Offset reference Date-aware Guam time conversion Japan Time Zone · UTC+09:00 neighbor Australia Time Zone · UTC+10 comparisons

Guam & Northern Mariana Islands: Same ChST Clock

The National Weather Service Guam identifies UTC+10 / ChST for both Guam and the Northern Mariana Islands. Modern Guam and Saipan therefore keep the same local clock. IANA keeps separate location identifiers—Pacific/Guam and Pacific/Saipan—so each location can preserve its own historical record even when their current rules match.

GuamPacific/Guam · ChST · UTC+10:00.
Northern Mariana IslandsPacific/Saipan · ChST · UTC+10:00.
Current differenceNone. Hagåtña and Saipan have the same civil time under current rules.
Oceania Time Zone Map Compare Pacific Locations
Visual Geography

See Guam on the Oceania Time Zone Map

For map-specific time-zone geography, use the Oceania regional map. It places Guam's UTC+10:00 clock within the western Pacific and shows its relationship to Australia, New Zealand and other Pacific island time zones.

Open Oceania Time Zone Map World Time Zone Map
Guam · ChST · UTC+10:00

Looking for the Current Time in Guam?

If your main question is what time or date it is in Guam right now, use the live territory clock. It includes the Pacific/Guam clock, visitor-local comparison and date-aware travel and calling utilities.

Territory ClockCurrent Time in Guam Regional Clock HubTime in Oceania Pacific ComparisonCurrent Time in Tahiti Dates & ObservancesWorld Holidays

Sources & Methodology

Guam's current ChST / UTC+10:00 and no-DST status are based on U.S. government time-zone references from NIST and the National Weather Service in Guam. The Pacific/Guam identifier and historical clock records are based on the IANA Time Zone Database. Live values on this page are calculated from the named IANA zone rather than from a manually fixed clock.

NIST — U.S. Time Zones & Guam DST Status National Weather Service Guam — ChST / UTC+10 Regional Reference IANA Time Zone Database — Pacific/Guam IANA tz Release Notes — Guam Historical DST Corrections

Last reviewed: August 21, 2026. IANA release 2026c is the latest tzdb release as of this review. Current Guam time is stable at UTC+10:00, but historical timestamps should remain location-based.

Guam Time Zone FAQ

What time zone is Guam in?

Guam uses Chamorro Standard Time (ChST), UTC+10:00, throughout the year.

How many time zones does Guam have?

Guam has one current civil time zone islandwide. Hagåtña, Dededo, Tamuning, Yigo and every other community use the same clock.

What is Guam's UTC offset?

Guam is UTC+10:00 all year under current rules.

Does Guam observe daylight saving time?

No. Guam does not currently change clocks and has no DST transitions in 2026.

What is the IANA time zone for Guam?

Pacific/Guam is the IANA time-zone identifier for Guam.

Is Guam the same time as the Northern Mariana Islands?

Yes. Guam and the Northern Mariana Islands both use Chamorro Standard Time at UTC+10:00 year-round.

How far ahead is Guam from New York?

Guam is 15 hours ahead when New York is on EST and 14 hours ahead when New York is on EDT.

How far ahead is Guam from Hawaii?

Guam is 20 hours ahead of Hawaii by wall-clock offset. The two locations are often on different calendar dates.

Is Guam the same time as Brisbane?

Yes under current rules. Guam and Brisbane both remain at UTC+10:00 year-round.

Did Guam ever observe daylight saving time?

Yes. IANA historical data records irregular DST use from 1959 through 1977. Guam's last recorded DST period ended on August 28, 1977.

Did Guam change its clock in December 2000?

No one-hour clock change occurred then. The IANA record changes the standard-time abbreviation from GST to ChST on December 23, 2000 while keeping the offset at UTC+10:00.